Use of an adsorbent and metering unit composed of adsorbent for this use

Abstract

The invention relates to the use of an adsorbent in a plant for treatment of liquids for removing dissolved organic and / or inorganic substances. It further relates to a metering unit composed of absorbent for this use. To provide an improved process for removing dissolved organic and / or inorganic substances in liquids with an absorbent it is proposed in the context of the invention, for removal of dissolved organic and / or inorganic substances, to meter a water-soluble metering unit containing an adsorbent into the liquid to be treated according to the amount of dissolved organic and / or inorganic substances to be removed, thus liberating the adsorbent. Upon metering into the liquid to be treated the metering unit is decomposed / dispersed to liberate the adsorbent which on account of the surface area which is then extremely large can bind large amounts of dissolved organic / inorganic substances.

Description

[0001] DESCRIPTION

[0002] Use of an adsorbent and dosing unit made of adsorbent for this use

[0003] The invention relates to the use of an adsorbent in a liquid treatment plant for removing dissolved organic and / or inorganic substances. It also relates to a dosing unit made of the adsorbent for this use.

[0004] It concerns in particular the use of an adsorbent in a plant for the treatment of liquids (such as municipal or industrial wastewater, drinking water, groundwater, lake / sea and river water, rainwater, mixed and street wastewater) with the aim of removing dissolved organic substances, such as dissolved organic carbon (DOC) or trace substances or micro-pollutants (for example pharmaceuticals, industrial and household chemicals) and / or inorganic substances such as phosphates, ammonium compounds or metals.

[0005] DE 10 2013 006 985 A1 describes a process for removing dissolved water constituents from drinking water, surface water, process water, or wastewater using powdered adsorbents. This process is used in process treatment in the chemical industry and in water and wastewater engineering, preferably in drinking water treatment and wastewater purification. It also describes a device for carrying out the process. An adsorbent, such as powdered activated carbon, is used to adsorb dissolved water constituents.

[0006] EP 0 530 396 A1 discloses a process for precipitating phosphates from phosphate-containing water using iron hydroxide. EP 3 957 608 A1 describes a process and a device for treating wastewater, in particular for removing micropollutants in a wastewater treatment plant, comprising a reactor having an inlet for the wastewater, a contact zone in which granulated activated carbon interacts with the wastewater, a supernatant zone, and an adjoining outlet from which the treated wastewater exits.

[0007] WO 2020 / 118513 A1 discloses a process for removing contaminants from water, in particular groundwater and drinking water, which comprises the following steps:

[0008] • Addition of submicron powdered activated carbon (sPAC) to an influent of water to be treated;

[0009] • Mixing the sPAC with the water to be treated;

[0010] • Introducing a mixture of sPAC and water into a sorption reactor for treatment;

[0011] • Leaving the mixture in the sorption reactor for a sufficient residence time to allow the sPAC to adsorb the contaminants in the water; and

[0012] • Transferring the mixture from the sorption reactor using a recycle pump to a high-speed ceramic membrane filter unit operating in cross-flow filtration, with the treated water being discharged as permeate and the sPAC being returned to the sorption reactor as retentate.

[0013] EP 2 536 497 A1 relates to an adsorptive system, in particular based on an agglomerate, comprising a plurality of adsorbent particles. The adsorbent particles are fixed, in particular adhered, to a binder carrier and bonded to the adsorptive system, in particular to an adsorbent, via the binder carrier. The adsorbent particles comprise a first particulate adsorption material and a second particulate adsorption material different from the first particulate adsorption material. Such an adsorptive system is used in the field of filter technology. EP 2 440 496 B1 discloses a device for treating an aqueous liquid by contacting it with a fluidized bed of coagulated carbon in powder form.

[0014] EP 3 009 405 A1 describes a process for water treatment to reduce the content of organic substances and pollutants, the process comprising:

[0015] • a first step of bringing the water to be treated into contact with a granular adsorption material, which is carried out in such a way that a contact time of the water with a granular adsorption material of 5 to 20 minutes is maintained,

[0016] • followed by a second step of clarifying the mixture of water and adsorption material from the first step, which leads on the one hand to the receipt of clarified water and on the other hand to the receipt of used granular adsorption material.

[0017] The adsorption material consists of agglomerates of activated carbon particles, with the agglomerates having an average size between 20 pm and 1,000 pm and an iodine number of more than 1,000 mg / g.

[0018] From EP 3 231 771 A1, a process for the treatment of water to reduce the content of organic materials and pollutants therein is known, the process comprising a step of bringing water to be treated into contact with an adsorbent granular material in a contact tank provided with stirring means; followed by a step of clarifying the water coming from the tank, which leads to the obtaining of clarified water and sludge, the adsorbent granular material consisting of agglomerates of activated carbon particles, the agglomerates having an average size of between 200 pm and 600 pm and a specific surface of between 800 and 1,000 m 2 / g.

[0019] Adsorptive structures based on agglomerates, each comprising a plurality of granular, preferably spherical adsorbent particles, as well as the production of these agglomerates and their use, are described in EP 2 349 556 B1. The adsorbent particles of the individual agglomerates are each bonded to one another via a preferably thermoplastic organic polymer, in particular a binder, or the adsorbent particles of the individual agglomerates are bonded and / or adhered to a preferably thermoplastic organic polymer, in particular a binder. The adsorptive structures are used for the adsorption of toxins, pollutants, and odors, in particular from gas or air streams or from liquids, in particular water.

[0020] EP 0 209 790 A2 describes a process for producing polymer-bound carrier masses containing fillers, the carrier masses obtained by this process and their use.

[0021] The object of the invention is to provide an improved process for removing dissolved organic and / or inorganic substances in liquids using an adsorbent.

[0022] This object is achieved according to the invention in that a water-soluble dosing unit containing an adsorbent is dosed into the liquid to be treated for the removal of dissolved organic and / or inorganic substances depending on the amount of dissolved organic and / or inorganic substances to be removed, whereby the adsorbent is released, wherein the adsorbent consists of particles of powdered adsorbent with a particle diameter d50 of 0.1 to 1,000 pm, preferably of 0.5 to 500 pm and particularly preferably of 1 to 100 pm.

[0023] In the form of dosing units, the adsorbent poses no explosion hazard. This allows for easy storage and handling. When dosed into the liquid to be treated, the dosing unit disintegrates or disperses, releasing the adsorbent, which, due to its extremely large surface area, can bind large quantities of dissolved organic / inorganic substances.

[0024] A preferred, but not exclusive, field of application of the adsorbent is wastewater treatment, particularly in chemical-biological systems (such as membrane bioreactors, SBR plants, single- or two-stage aeration processes, processes with aerobic and / or anaerobic granules) and / or after chemical-biological systems, such as in the so-called fourth treatment stage.

[0025] A preferred embodiment of the invention is that the adsorbent is selected from the group consisting of activated carbon, bentonite, zeolite, polymeric adsorbents, iron oxide, iron hydroxide, silica gel or mixtures thereof.

[0026] In principle, any adsorbent capable of adsorbing dissolved, preferably organic / inorganic, substances is suitable. These can be, for example, anthropogenic organic trace substances (such as pharmaceutical active ingredients, X-ray contrast agents, substances from personal care and cleaning products, biocides, flame retardants, perfluorinated chemicals) and / or organic carbon compounds and / or inorganic substances such as phosphates, ammonium compounds, or metals. The adsorbent can be composed of activated carbon, bentonite, zeolite, polymeric adsorbents, iron oxide, iron hydroxide (such as ß-FeOOH (akaganeite)), or silica gel, as well as mixtures thereof.The raw material of the adsorbent is in powdered and / or suspended form (for example, in the case of activated carbon: powdered activated carbon (PAC) and / or superfine powdered activated carbon (sPAC)) and consists of substances that are tailored to the dissolved organic and / or inorganic substances, or the liquid matrix.

[0027] The dosage unit can be in the form of a pill produced by pressing / freeze-drying / 3D printing / casting / extruding the powdered / suspended adsorbent. Such a pill can be produced from powdered adsorbent alone, for example, by pressurization / freeze-drying and / or by adding binders and / or disintegrants. The binders and / or disintegrants must be selected such that the adsorbent is released upon contact with liquid.

[0028] It is also possible for the dosage unit to be in the form of a capsule, in which a hard or soft water-soluble shell encloses the powdered adsorbent.

[0029] The dosing unit can also be in the form of a pod, with a hard or soft water-soluble shell enclosing the suspended adsorbent.

[0030] In this context, it is also possible that the adsorbent is in foamed form.

[0031] The shape, size, and composition of the dosing unit, and any enclosure, are designed to ensure optimal reaction between the adsorbent and the substances to be removed in the liquid matrix, depending on the specific process. For example, the dosing units can be introduced into the process chain at points with high turbulence or high energy input, which supports the release and even distribution of the adsorbent.

[0032] However, the timing of the release can also be specifically controlled by the design of the dosing unit, for example, the choice of its casing, so that a continuous introduction of the adsorbent occurs. It is only necessary to ensure that the dosing unit decomposes upon contact with the liquid, or rather the organic / inorganic substances. To support the release of the adsorbent, process-related units (such as agitators or macerators) can be specifically employed or utilized. Furthermore, a pre-release outside the liquid to be treated and subsequent targeted introduction into the process stream with a separate unit is possible. A further development of the invention consists in the dosing unit comprising additives.

[0033] In this context, the invention provides that the additives are selected from the group consisting of metal salts, iron oxide, iron hydroxide, polymers and binders or disintegrants.

[0034] The additives are used in particular for the agglomeration of the adsorbent and for supporting the release of the adsorbent after contact of the dosing unit with the liquid and for the separation of the adsorbent in separation processes, such as sedimentation and / or flotation and / or filtration as well as for the precipitation of dissolved substances (such as phosphates, metals) and / or for supporting the above-mentioned separation process.

[0035] A preferred embodiment of the invention is that the metal salts comprise di- or trivalent iron and aluminum salts.

[0036] It is advantageous that the polymers are selected from cationic, anionic and non-ionic polymers.

[0037] It is advantageous that the binder (to hold the adsorbent together) or the disintegrant (to support the release of the adsorbent) are selected from biodegradable substances (such as polyvinyl alcohol, polyvinylpyrrolidone, gelatin, (microcrystalline) cellulose, carrageenan, starch, starch esters, glucose, lactose, sucrose, maltodextrin, polyacrylic acid, collidone, protein) or non-biodegradable substances (such as salts). It is advantageous that the binders or disintegrants are selected from readily biodegradable compounds. The readily degradable compounds can then serve as a nutrient source for downstream separation processes where biological processes are to be supported. Within the scope of the invention, the additives can be present in both crystalline and powder form.

[0038] In the case of additives in solid form, these can be present either in the form of an additive coating on the adsorbent or a coating of the adsorbent that dissolves upon contact with liquid, or essentially homogeneously distributed in the adsorbent.

[0039] Alternatively, the additives can also be in liquid and / or suspended form.

[0040] The invention also provides a dosing unit for use in the process according to the invention, which is water-soluble and comprises at least one adsorbent selected from the group consisting of activated carbon, bentonite, zeolite, polymeric adsorbents, silica gel or mixtures thereof and at least one additive selected from the group consisting of metal salts, iron oxide, iron hydroxide, polymers and binders or disintegrants, wherein the adsorbent forms a hollow dosing unit which encloses the additive.

[0041] Also within the scope of the invention is a dosing unit for use in a process which is water-soluble and comprises at least one adsorbent selected from the group consisting of activated carbon, bentonite, zeolite, polymeric adsorbents, silica gel or mixtures thereof and at least one additive selected from the group consisting of metal salts, iron oxide, iron hydroxide, polymers and binders or disintegrants, wherein the additive forms a hollow dosing unit which encloses the adsorbent.

[0042] In the case of liquid additives, a hollow dosing unit can be formed from the adsorbent, enclosing the liquid additives. When the adsorbent is released, the liquid additives contained therein are also released. Conversely, it is also possible for the adsorbent to be in liquid or foamed form and enclosed in a shell of solid additives to form the dosing unit.

[0043] The invention also relates to a dosing unit for use according to the invention, wherein the dosing unit is water-soluble and comprises an adsorbent selected from the group consisting of activated carbon, bentonite, zeolite, polymeric adsorbents, silica gel or mixtures thereof and additives selected from the group consisting of metal salts, iron oxide, iron hydroxide, polymers and binders or disintegrants.

[0044] It is within the scope of the invention that the additives are in powder form and are preferably present in the form of an additive coating on the adsorbent or a coating of the adsorbent which dissolves upon contact with liquid or are distributed substantially homogeneously in the adsorbent.

[0045] Alternatively, it is also advantageous for the additives to be in liquid form and preferably for a hollow adsorbent to be present which encloses the liquid additives.

[0046] Examples of designs of the dosing units are explained in more detail below.

[0047] 1 . Dosage unit in the form of a pill:

[0048] • Adsorbent: PAH with a grinding fineness of 80% < 40 pm; 500 mg activated carbon / pill

[0049] • Additives: polyvinylpyrrolidone, alginate

[0050] • Production of the pill by pressing the powdered adsorbent mixed with the additives under high pressure

[0051] 2. Dosing unit in the form of a capsule:

[0052] • Adsorbent: o PAH with a grinding fineness of 80% < 40 pm; 100 mg / capsule o Bentonite with a grinding fineness of 80% < 40 pm; 100 mg / capsule

[0053] • Additives: Gelatin

[0054] • Production: The additives are in the form of a capsule that encloses the powdered adsorbent

[0055] 3. Dosing unit made of an adsorbent coated with a water-soluble additive:

[0056] • Adsorbent: o sPAK with a grinding fineness of 80% < 5 pm; 200 mg / capsule o Bentonite with a grinding fineness of 80% < 40 pm; 50 mg / capsule

[0057] • Additives: Polyvinyl alcohol; Iron(II) chloride, starch

[0058] • Production: Pressing the powdered adsorbent under high pressure, applying a coating of the additives to the compressed adsorbent

[0059] Figures 1 to 5 show embodiments of the dosing unit according to the invention.

[0060] It shows

[0061] Fig. 1 a dosage unit in the form of a pill,

[0062] Fig. 2 a dosing unit in the form of a capsule,

[0063] Fig. 3 a dosing unit in the form of an adsorbent-additive composite with a water-soluble coating,

[0064] Fig. 4 a dosing unit in the form of an additive jacket filled with a liquid adsorbent,

[0065] Fig. 5 shows a foamed adsorbent-additive composite. As can be seen from Fig. 1, the dosing unit can be in the form of a pill, which is produced by pressing adsorbent 1, optionally with the addition of binders and optionally further additives.

[0066] Fig. 2 shows a dosing unit in the form of a capsule. This can be either a hard capsule or a soft capsule. In this case, a powdered adsorbent 1 is contained in a capsule containing water-soluble additive 2(s). Upon contact with water, the capsule dissolves, releasing adsorbent 1 and additive 2(s).

[0067] Fig. 3 shows a dosing unit in the form of a composite of adsorbent 1 and one or more solid additives 2, surrounded by a water-soluble coating 3, as is known from dishwasher tablets. The coating 3 can also consist of another additive.

[0068] Fig. 4 shows a dosing unit in the form of a liquid adsorbent 1 surrounded by a solid shell of one or more additives 2. Conversely, one or more liquid additives could also be surrounded by a solid shell of an adsorbent.

[0069] Fig. 5 shows that a foamed adsorbent-additive composite can also be present.

Claims

Claims: Use of an adsorbent in a liquid treatment plant for the removal of dissolved organic substances, characterized in that a water-soluble dosing unit containing an adsorbent is dosed into the liquid to be treated for the removal of dissolved organic and / or inorganic substances, depending on the amount of dissolved organic and / or inorganic substances to be removed, wherein the adsorbent is released, the adsorbent consisting of particles of powdered adsorbent with a particle diameter dso of 0.1 to 1,000 pm, preferably of 0.5 to 500 pm and particularly preferably of 1 to 100 pm. Use according to claim 1, characterized in that the adsorbent is selected from the group consisting of activated carbon, bentonite, zeolite, polymeric adsorbents, iron oxide, iron hydroxide, silica gel or mixtures thereof.Use according to any one of the preceding claims, characterized in that the dosing unit comprises additives. Use according to claim 3, characterized in that the additives are selected from the group consisting of metal salts, iron oxide, iron hydroxide, polymers, and binders or disintegrants. Use according to claim 4, characterized in that the metal salts comprise divalent or trivalent iron and aluminum salts. Use according to claim 4, characterized in that the polymers are selected from cationic, anionic, and nonionic polymers.

7. Use according to any one of claims 3 to 6, characterized in that the additives are in solid form.

8. Use according to claim 7, characterized in that the additives are present in the form of an additive coating on the adsorbent or a coating of the adsorbent which dissolves upon contact with liquid or are distributed substantially homogeneously in the adsorbent.

9. Use according to any one of claims 3 to 6, characterized in that the additives are in liquid form.

10. Use according to claim 9, characterized in that a hollow adsorbent is present which encloses the liquid additives.

11. Dosing unit for use in a process according to claims 1 to 10, characterized in that the dosing unit is water-soluble and comprises at least one adsorbent (1) selected from the group consisting of activated carbon, bentonite, zeolite, polymeric adsorbents, silica gel or mixtures thereof and at least one additive selected from the group consisting of metal salts, iron oxide, iron hydroxide, polymers and binders or disintegrants, wherein the adsorbent (1) forms a hollow dosing unit enclosing the additive (2).

12. Dosing unit for use in a process according to claims 1 to 10, characterized in that the dosing unit is water-soluble and comprises at least one adsorbent (1) selected from the group consisting of activated carbon, bentonite, zeolite, polymeric adsorbents, silica gel or mixtures thereof and at least one additive selected from the group consisting of metal salts, iron oxide, iron hydroxide, polymers and binders or disintegrants, wherein the additive (2) forms a hollow dosing unit enclosing the adsorbent (1).

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